Hitherto, theories of similarity have restricted themselves to judgments of what might be called literal similarity. A central thesis of this article is that a complete account of similarity needs also to be sensitive to nonliteralness, or metaphoricity, an aspect of similarity statements that is most evident in similes but that actually underlies metaphorical language in general. Theoretical arguments are advanced in support of the claim that metaphoricity can be represented in terms of the relative degrees of salience of matching (or matchable) attributes of the two terms in a comparison. A modification of Tversky's account of similarity is proposed. The implications of this proposal for similarity statements are discussed, along with implications for the psychological processes involved in their comprehension. It is argued that the general account of similarity proposed, including, as it does, nonliteral similarity, can form not only the basis of a theory of metaphor but can also give a credible account of the relationship between metaphor, analogy, and similarity.